Fruit fly study shows food choice decisions require taste input

The fruit fly has multiple taste organs throughout its body to detect chemicals, called tastants, that signal whether a food is palatable or harmful. It is still unclear, however, how individual neurons in each taste organ act to control feeding. To explore this question, a team used the fly pharynx as a model to study whether taste information regulates sugar and amino acid consumption at the cellular level.

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What can the fruit fly teach us about taste and how chemicals cause our taste buds to recognize sweet, sour, bitter, umami, and salty tastes? Quite a lot, according to University of California, Riverside, researchers who have published a study exploring the insect’s sense of taste.

“Insect feeding behavior directly impacts humans in many ways, from disease-carrying mosquitos that seek human blood to pests whose appetite can wreak havoc on the agricultural sector,” said Anupama Dahanukar, an associate professor of molecular, cell and systems biology, who led the study appearing in the Journal of Neuroscience.

“How insect taste neurons are organized and how they function is critical for a deeper understanding of their feeding behavior.”

The fruit fly has multiple taste organs throughout its body to detect chemicals, called tastants, that signal whether a food is palatable or harmful.  It is still unclear, however, how individual neurons in each taste organ act to control feeding.

EPA invites input on identifying new organisms which should be deregulated

The Environmental Protection Authority (EPA) is seeking input on which new organisms should no longer hold regulatory status as “new” because they are effectively resident in New Zealand.

This deregulation process is conducted under the Hazardous Substances and New Organisms (HSNO) Act, for species that arrived after 29 July 1998 and are now established in this country.

One example is the Varroa mite, which was first identified in Auckland in 2000 and then spread throughout New Zealand. Scientific research was limited by regulatory barriers, so the mite was deregulated in 2011 to help researchers develop pest management options.

When this process was last run in 2018, five organisms were deregulated including a ladybird (Harmonia axyridis), a bacterium (Komagataeibacter xylinus), and a virus (Listeria phage P100).

The EPA is now starting with a clean slate, and asking public sector organisations, Crown Research Institutes, academics, and the public to submit candidates for a new round of deregulation.

Proposing a candidate does not guarantee a change in its regulatory status. Organisms are assessed on a case-by-case basis and, once the Minister for the Environment has decided on a shortlist, further public consultation will take place.

“This process is about freeing up regulatory barriers, including making it easier for scientists wanting to conduct research on these organisms, and removing the unnecessary financial costs involved,” says the EPA’s General Manager of Hazardous Substances and New Organisms, Dr Chris Hill.

The EPA is responsible for evaluating and managing the risks of introducing new organisms into New Zealand, under the HSNO Act. All hazardous substances and new organisms must be approved before they can be imported or used in this country.

Submissions close at 5pm on 6 May.

Read more about the EPA’s call for candidates

Read about changing the status of a new organism

Source:  Environmental Protection Authority

EPA approves new weaponry for the war on wasps

Approval has been granted to import and release two new organisms, a hoverfly and beetle, in a bid to reduce plague populations of invasive German and common wasps in New Zealand.

The Tasman District Council applied to introduce the wasp-nest beetle, Metoecus paradoxus, and a hoverfly, Volucella inanis, for biological control of the wasps Vespula germanica and V. vulgaris.

The application quotes research that these wasps cost the New Zealand economy $133 million annually, in damages and management. It says beech forests at the top of the South Island have the highest densities of wasps in the world. There can be up to 30 wasp nests per hectare, each containing many thousands of wasps which kill honey bees and native insects like caterpillars and spiders.

In its application to the Environmental Protection Authority (EPA), Tasman District Council said using the hoverfly and beetle as biological control agents would be a sustainable option to target hard-to-reach wasp populations, and would reduce the damage they cause.

The EPA has found no evidence of either the beetle or hoverfly attacking non-target species, and there are no native or exotic species they could breed with.

Following public consultation late last year, an EPA decision-making committee has now granted approval without controls for the release of the hoverfly and beetle in New Zealand.

“Invasive wasps pose a significant threat, having a negative impact on biodiversity and the food supply of native insects and birds such as kākā and tūī. The wasps also attack beehives, resulting in reduced pollination and honey production,” says the EPA’s General Manager of Hazardous Substances and New Organisms, Dr Chris Hill.

“We are pleased to be playing our part to support conservation and our primary industries.”

The EPA is responsible for evaluating and managing the risks of introducing new organisms into New Zealand, under the Hazardous Substances and New Organisms Act. All hazardous substances and new organisms must be approved before they can be used in this country.

Read the decision (PDF, 574KB)
Read more about biological control agents

Source:  Environmental Protection Authority

Hawke’s Bay community is engaged in codling moth research to protect New Zealand apples

Plant & Food Research has engaged households in Hawke’s Bay, the heart of New Zealand’s apple industry, in studies that will help create smarter and more sustainable ways to protect the prized fruit and those whose livelihoods depend on it.

New Zealand is the only country which can export apples to some of the world’s most exclusive and premium markets such as Japan. To maintain this status, our apple exports must be free of pests like codling moths as well as contain low chemical residues.

Thanks to decades of innovation and integrated pest management practice, the codling moth population on-orchard is largely under control, but the industry is not necessarily out of the woods.

Plant & Food Research scientists and their research partners at the University of Auckland have obtained permission from households in Hastings City, a peri-urban (semi-rural) area close to commercial apple orchards, to install 200 pheromone traps on residential properties. Some of these households have apple and walnut trees in their gardens – both common host trees of codling moths.

Responses of Queensland fruit fly females to fruit odours are studied

Plant & Food Research scientists, as part of the Better Border Biosecurity (B3) research collaboration, and collaborators at the Institut Agronomique néo-Calédonien, have been collecting and analysing the odours of four ripe fruit hosts in a project aimed at developing a female attractant for Queensland fruit fly surveillance.

The work is the subject of a post on Plant & Food Research’s website.

Females of the Queensland fruit fly (QFF), Bactrocera tryoni, are among the most damaging pests of horticulture in the South Pacific. New Zealand is at high risk of incursions and deploys a national surveillance system for early detection, to enable a fast eradication response.

Current detection relies on a parapheromone lure for males of the species. But no long- lasting attractants for female QFF exist, which excludes the half of the population which causes the most damage.

In their research aimed at developing a female attractant for surveillance, the collaborating scientists from Plant & Food Research and the Institut Agronomique néo-Calédonien collected and analysed the odours of four ripe fruit hosts (known and potential) – orange, cherry guava, banana, and feijoa.

Using gas-chromatography coupled with electro-antennographic detection (EAD), the researchers detected 41 compounds that stimulated a response in the female fruit fly, seven of which were found to be common for more than one fruit.

Overall, mated females responded more often and with higher intensity than virgin females, as expected when mated females search for fruit to oviposit (lay eggs).

The 26 compounds that triggered the largest and most frequent responses in female QFF, were tested in an olfactometer – a device designed to analyse the behavioural response of live insects to an odour stimulus. In contrast to the EAD measurement, behavioural responses did not show strong differences between mated and virgin females, although they did differ significantly between the compounds.

No correlation was detected between the electrophysiological and behavioural responses.

Field testing with the behaviourally active compounds is being carried out in Australia, for the development of a lure for female Queensland fruit fly.

This work was performed with the support of a Pacific Fund from the Foreign Ministry of France. This project was funded by Horticulture Innovation Australia Limited with co-investment from The New Zealand Institute for Plant and Food Research Limited and support from the Better Border Biosecurity collaboration (b3nz.org.nz).

Journal Reference
Mas F, Manning L, Singlet M, Butler R, Mille C, Suckling DM 2020 Electrophysiological and Behavioural Responses of Queensland Fruit Fly Females to Fruit Odors J Chem Ecol 46 (2) https://doi.org/10.1007/s10886-019-01143-8

Source:  Plant & Food Research

Flowering alyssum can help to protect brassica crops

A common garden plant may hold the key to protecting brassica crops from the wheat bug, Nysius huttoni, a damaging pest.

In a paper just published in the journal Agricultural and Forest Entomology, Sundar Tiwari, who has just completed his PhD through the Bio-Protection Research Centre, outlines his research into protecting brassica seedlings from the wheat bug.

It shows that alyssum (Lobularia maritima L. Desvaux cv. Benthamii White) planted around the perimeter of a brassica field protects the seedlings by “trapping” wheat bugs.

Trap cropping is a form of companion planting, using one plant to keep insect pests away from nearby plants. It can help to reduce the need for insecticide.

AgResearch finds pasture pests costing economy billions

Pests most commonly targeting New Zealand’s pastures are costing the economy up to $2.3 billion a year, an AgResearch study has found.

The study is the first of its kind to estimate the financial impact of invertebrate pests such as the grass grub, black beetle, nematodes and weevils in terms of lost productivity for pastoral farming.

The full science paper has been published this week in the New Zealand Journal of Agricultural Research and can be found HERE.

Of the total estimated annual losses of between $1.7 billion and $2.3 billion in `average’ years, up to $1.4b billion occurs on dairy farms, and up to $900 million on sheep and beef farms.

“Our research shows that the impact of the grass grub alone costs dairy farms up to $380 million, and sheep and beef farms up to $205 million, each year,” says AgResearch scientist Colin Ferguson.

Losses attributable to these pasture pests are usually determined either on the basis of the amount of foliage they consume, or reductions in pasture production.

However, AgResearch’s study has used the reduction in pasture production to estimate the impact on milk production revenue for dairy farms, and on meat production revenue for sheep and beef farms.

“What this provides us is a good picture of the challenge we and farmers face with pasture pests, and it reinforces the need to invest in new and cost-effective ways to better control these pests,” Mr Ferguson says.

“AgResearch is looking at pest control on a number of fronts, including the development of new biopesticides – naturally occurring organisms that can be used to target specific pest species, instead of chemical treatments that can be expensive and have unwanted impacts on the environment.”

The study was initiated as part of Pastoral 21 Next Generation Dairy Systems and funded by DairyNZ, Fonterra, Dairy Companies Association of New Zealand, Beef + Lamb New Zealand and MBIE – and has been completed with funding from AgResearch.

Source: AgResearch

Drive is under way to rid communities of wasps

Invasive “social” wasps are putting major pressure on New Zealand’s biodiversity and cost the economy an estimated $130 million a year, Radio NZ reminded us today.

That figure comes from a 2015 Department of Conservation study (HERE) which assessed the economic impact of German wasps and common wasps across industries, society and the natural environment in New Zealand.

The report said the biggest economic impacts were on farming, beekeeping, horticulture and forestry workers.

This assessment was based on a literature review. Information was collected from previous studies and from affected sectors in New Zealand to estimate the total costs of wasps, ie the costs that could be avoided and the opportunities that could be gained if wasps were not present in New Zealand.

New Zealand has some of the highest densities of German and common wasps in the world. Wasps have huge social and biological impacts; they are one of the most damaging invertebrate pests in New Zealand, harming our native birds and insects.

The DOC study found the major financial impact was on primary industries and the health sector and included:

• more than $60 million a year in costs to pastoral farming from wasps disrupting bee pollination activities, reducing the amount of clover in pastures and increasing fertiliser costs.
• almost $9 million a year cost to beekeepers from wasps attacking honey bees, robbing their honey and destroying hives.
• wasp-related traffic accidents estimated to cost $1.4 million a year.
• over $1 million each year spent on health costs from wasp stings.
• on top of the direct costs, almost $60 million a year is lost in unrealised honey production from beech forest honeydew which is currently being monopolised by wasps. Honeydew is also a valuable energy source for kaka, tui and bellbirds.

Radio NZ today described the invasive common wasp (aka Vespula Vulgaris), the German wasp, and our three species of paper wasp as being among “our most-hated introduced pests”.

The Royal Society, the Department of Conservation and some local communities are dedicating time, money and energy into putting an end to their predatory behaviour, which affects birds, bats, bees and other insects.

Entomologist and author of The Vulgar Wasp Phil Lester has been talking with Simon Morton about New Zealand’s problem wasps and the latest ways of keeping them under control, which include insecticides and genetic manipulation.

You can listen here to the interview (duration15′ :02″)

Source: Radio NZ

Initial successes reported after the release of rabbit-killing virus in Otago

A new virus introduced to fight plagues of the rabbit pest in Otago is taking effect, Radio New Zealand reports (HERE).

Field samples from the Otago Regional Council showed the K5 strain of the rabbit haemorrhagic disease is killing its targets.

The council’s director environmental monitoring and operations, Scott MacLean,  welcomed the initial data but cautioned that the virus will not be widespread yet.

It will continue to spread for 12 to 14 weeks, he said.  Land owners should plan secondary controls for winter.

Reporting earlier this year on the release of the rabbit virus across the country, including 100 sites in Otago, Stuff said officials hoped to kill more than 40 per cent of the pest population.

The Stuff report (HERE) explained that the K5 virus is a Korean variant of a strain that is already in New Zealand, after it was illegally released here in 1997 by a collective of vigilante Otago farmers.

Mr MacLean told Stuff at that time the approval of K5 was good news.

“Rabbits are the number one pest in Otago. Ten rabbits can eat as much grass as one sheep. They are a threat to our biodiversity, not to mention the soil degradation and loss of soil caused by rabbit holes and warrens.

“The K5 virus, which only affects the European rabbit, may give us the opportunity to reduce rabbit numbers to the level where they are manageable. It will be especially beneficial in areas where traditional rabbit management methods are either not possible or not acceptable.”

Environment Canterbury applied in November to the Ministry for Primary Industries for approval to introduce and use the Rabbit Haemorrhagic Virus Disease RHDV1-K5 for pest rabbit management.

ECan regional leader biosecurity Graham Sullivan said the virus would be released in March and April, but would not eradicate the population.

“While not the silver bullet for rabbit control, we anticipate that the new strain will greatly assist the control of wild rabbit populations by supplementing more traditional control methods.

“The controlled release will use a high-quality commercially prepared product at selected sites identified by participating local councils.”

 
The virus would be spread nationally in a coordinated programme. There would be more than 100 release sites in Otago and the council would coordinate the release to make sure it had maximum impact, MacLean said.

“These sites were selected based on science to ensure we have the best chance of creating an epidemic and a high knock-down (kill) rate.”

The virus is not being introduced without opposition.

Rabbit Council of New Zealand member Gary Stephenson, who submitted against ECan’s application, feared rabbit owners had not been given enough time to get their animals vaccinated against the “abhorrent” virus.

“There are thousands of rabbit owners up in arms and really, really worried about this … The pet rabbit population deserves the same care and protections from government and the animal welfare rights [groups] as pet cats and dogs … There are many other means of controlling wild rabbits that do not threaten pet rabbits or treat pet rabbits as collateral damage.

“I have been fighting this since June 2015 … It’s absolutely abhorrent.”

Mr Stephenson said it took 21 days for a vaccination to be effective, which did not give pet rabbit owners much time.

Rabbits infected with K5 develop symptoms between 24 hours and 72 hours after infection and usually die within six hours to 36 hours after the first symptoms appear.

More information can be found on the Ministry for Primary Industries’ website HERE. 

“Quiet forest” claims are dispelled by bioacoustics study of 1080 effects

The use of the toxin sodium monofluoroacetate (otherwise known as 1080) for possum eradication has long raised concerns that a heavy toll is being taken on wildlife and the environment.

The Department of Conservation – supported by farm organisations among others – says it is the most suitable poison for aerial drops to kill possums which are destroying native bush. Destroying possums limits the spread of tuberculosis from the pests to livestock on farms.

But 1080’s critics say the poison kills not only pests, but also native birds and wildlife such as kiwi. Moreover, it is a cruel method of pest control and may contaminate the ground and waterways.

On  Radio New Zealand’s Nine to Noon programme this morning, Roald Bomans told of studies to investigate the claim that aerial 1080 drops cause forests to fall silent.

He used bioacoustics, a developing area in ecology, to monitor native bird species in the Remutaka and Aorangi Ranges.

He did this by listening to recordings and developing a special detector for morepork calls.

Collectively his bioacoustic monitoring showed no negative impact on the populations of native bird species.

The interview can be heard HERE.

It follows a seminar led by Roald Bomans at Victoria University last month.

According to his notes on the university website (HERE) about the seminar :

I used recordings from autonomous recording units (ARUs) to monitor resident bird species over multiple aerial 1080 operations in order to investigate this claim.

The total amount of birdsong recorded did not decrease significantly in treatment areas relative to non-treatment areas. The calling prevalence of one species, the introduced chaffinch (

Diurnal monitoring was conducted for 10-12 weeks over two independent operations. The total amount of birdsong recorded did not decrease significantly in treatment areas relative to non-treatment areas. The calling prevalence of one species, the introduced chaffinch (Fringilla coelebs), showed a significant decline in the treatment area across one of the two operations monitored. Collectively, these results suggested no negative impact of modern 1080 operations on the populations of native bird species.

Extracting data from ARU recordings can be labour intensive.

In the second part of my study I developed a process for developing a parsimonious template-based detector in an efficient, objective manner and applied this method to the creation of a detector for morepork (Ninox novaeseelandiae) calls.  The method was highly successful as a directed means to achieve parsimony. In independent validation tests, the final detector had a high precision (0.939) and moderate sensitivity (0.399).

This detector was used to monitor morepork in treatment and non-treatment areas across three independent aerial 1080 operations. Morepork showed no significant difference in trends of calling prevalence across the three operations monitored. Over a longer time period, a significant quadratic effect of time since 1080 treatment was found, with calling prevalences predicted to increase for 3.5 years following treatment.

Collectively, the results suggest a net-positive effect of modern 1080 mammal control on morepork populations.